Paint strippers typically used for removal of polymeric coatings contain solvents, water, surfactants, evaporation retardants, corrosion inhibitors, viscosity modifiers, and activators. Solvents are typically volatile solvents or low-vapor pressure solvents that are biodegradable. Surfactants promote wetting, emulsification flow, and penetration. Evaporation retardants are materials of limited solubility which film out of solution forming a barrier, such as petroleum waxes, petroleum aliphatics, cetyl alcohol, and polyglycols. Viscosity modifiers are predominantly cellulose derivatives, though finely divided silica ground clay and synthetic polymers are also used. Corrosion inhibitors are quite diverse, and specific to the metal involved and the stripper composition. Activators break chemical bonds in polymers by hydrolysis, ester interchange, oxidation or reduction.
The more environmentally acceptable paint removers in use contain low-vapor pressure solvents with ammonia, amines, formic acid or other organic acids. U.S. Pat. No. 5,215,675 to Wilkins et al. relates to a stripping composition containing peroxide, however, the pH of the composition is significantly below the pH of the compositions of the present invention. A low pH is disadvantageous since a surface, especially a metal surface, is corroded by acidic solutions. U.S. Pat. No. 3,654,940 to Ritzi relates to a stripping composition where heat is used to activate the composition, in contrast to the present invention where mixing of the stable stock solutions activates the ingredients. U.S. Pat. No. 3,355,385 to Mackley relates to processes that use hydrogen peroxide as the bond release agent in stripping organic coatings; the compositions are not as stable as those of the present invention, nor do they have pH values as those of the present invention to avoid corrosion of the substrate. In general, peroxide-containing stripping agents have heretofore been somewhat limited in use due to their lack of stability, hazards in use, and corrosiveness to metals; particularly to cadmium-coated fasteners, such as rivets and the landing gears of aircraft.